Turning Off Drupal 7's Cache

Is there a way to run Drupal 7 in a "non-cache" mode while developing new modules? My specific need is to turn off any caching of modules and/or module information during development so I don't need to clear the cache when I make my changes, but generally when learning a new system I prefer its internal cache be off since I haven't yet learned what changes require a cache clearing, and what don't (i.e. "Am I doing this wrong, or are the old results just cached?"

Also, is there a way to quickly clear out the Drupal cache from the command line (instead of having to use the application UI in the performance section)